Study of rabbit corneal epithelial keratins, important cytoskeletal proteins, indicate that there is a change in the expression of these proteins during epithelial wound repair. The significance of this change is unknown. It is our working hypothesis that the change in keratin proteins indicate a change in the differentiated state of the epithelial cell and is therefore an important, primary epithelial response to injury. Furthermore, the change in keratin/cell differentiation may be involved in key process of epithelial wound healing including cell proliferation as mediated by cellmatrix interactions. The proposed studies seek to identify the relationship between corneal epithelial keratin/cell differentiation and th process of epithelial wound repair. Understanding these relationships may be fundamental to our understanding of normal and defective epithelial repair. The major objective of the proposed studies is to more clearly define the changes in keratin protein expression in terms of their relationship to cell proliferation and the subjacent extracellular matrix. These studies are designed to determine: 1) if the change in keratin protein expression is related to changes in the subjacent matrix,fibronectin (Fn), fibrin (Fg), laminin (Ln), pemphigoid antigen (PA), type IV and VII collagen, and/or formation of hemidesmosomes; and 2) if the change in keratin expression is associated with epithelial proliferation. The methods used to achieve these objectives include biochemical (SDS-PAGE, 2D gel electrophoresis, immunoblot) and morphologic (immunofluroescent, TEM, and autoradigraphic) methods in the analysis of keratin proteins (as identified by mouse monoclonal antibodies), subjacent matrix glycoproteins (as identified by antibodies to Fn, Fg, Ln, PA, type IV and VII collagen) and attachment sites (hemidesmosomes - TEM) and cell proliferation (3H-thymidine uptake) in regenerating epithelium following standardized corneal wounds that either include or spare the basal lamina.